1. Field of the Invention
The present invention relates to a belt lock for locking a belt. Specifically, the invention relates to a belt lock including a base and an attachment to be detachably attached to the base, the attachment having a belt attaching section for attaching a belt.
2. Description of Related Art
As a belt lock for locking a belt, there has been known a buckle that can connect a plurality of belts to each other and separate the plurality of belts from each other. For example, as a buckle that can connect five seatbelts (a crotch belt, right and left waist belts, right and left shoulder belts) to each other and separate the five seatbelts from each other, a five-direction buckle has been known (see, for example, Document 1: JP-A-9-308508 and Document 2: U.S. Pat. No. 6,543,101).
The buckle includes: a socket; a pair of plugs to be disengageably inserted in the socket from openings on right and left sides of the socket; and attachments to be slidably attached to upper edges of the plugs. The socket includes a crotch belt attaching section for attaching the crotch belt. The plugs on the right and left sides each include a waist belt attaching hole for attaching the right or left waist belt. The attachments each include a shoulder belt attaching hole for respectively attaching the right and left shoulder belts. The plugs each include a rail with which a groove of the respective attachments is engaged. The rail has a stopper on an outer end of the rail.
In use, the attachments are firstly slid along the respective rails of the plugs to be attached to the plugs, and the plugs are inserted in the socket from the openings on the right and left sides of the socket to be engaged with the socket. Each of the attachments attached to the plugs is sandwiched by the stopper of the plug and a stopper of the socket, so that the attachments are prevented from dropping from the respective plugs.
Hence, even when tensile force is applied on the seatbelts (the crotch belt, the right and left waist belts, and the right and left shoulder belts), the plugs do not become disengaged from the socket and the attachments do not become disengaged from the plugs, so that the seatbelts are securely connected.
With the buckle having the above-described structure, when the plugs are inserted in and engaged with the socket, the attachments do not become disengaged owing to the stoppers of the plugs and the socket. However, when the plugs are disengaged from the socket, the attachments may become disengaged from the respective plugs. Specifically, when the plug is disengaged from the socket, the attachment may become disengaged from the plug contrary to the intention of an operator since the stopper of the socket does not act on the attachment.
In a general use, disengaging the plugs from the socket enables the shoulder belts to slip off the shoulders of an infant, so that it is not necessary to disengage the attachments from the plugs.
However, if the attachment is disengaged from the plug when the plug is disengaged from the socket, an operation for engaging the plug and the socket becomes complicated, which is not preferable. Concretely, because it becomes necessary to do an additional operation of attaching the attachment to the plug before inserting the plug into the socket for re-engagement, the operation for engaging the plug and the socket becomes complicated.